This invention relates to solar energy devices and systems and, more particularly, to such devices and systems for use in conjunction with a building or structure to be heated and/or cooled.
There have been previously devised numerous schemes for utilizing solar energy to heat or cool buildings. The cost of implementing these schemes has generally not been competitive with systems using fossil fuels, but the increasing costs of such fuels has made solar energy prospects more attractive, where when initial investment costs may be high. Nevertheless, many proposed solar energy systems are found to suffer from practical disadvantages which detract from their ultimate usefulness.
Various prior art systems for capturing the sun's energy require very large area solar collectors or reflectors, the size of which is an especially limiting factor in such important applications as city office buildings. Other proposed systems require radical and expensive modification of a building's structural design or involve inconvenient or unsightly alternatives, such as dedicating a full building wall to solar collection or using otherwise available window space for such collection. A technique which attempts to overcome the latter disadvantage is disclosed in U.S. Pat. No. 3,107,052 wherein a liquid is contained between inner and outer transparent window walls, the liquid being intended as a heat exchanging medium which can be pumped. However, this scheme is limited, inter alia, by the thermodynamic properties of a system where the absorbing medium is in contact with the external wall. Also, potential leakage of the liquid poses a practical problem. A further disadvantage of this and other prior art systems is their lack of flexibility in adapting to changing environmental conditions. For example, some solar collectors must be masked or covered for part of the day or year. Others require expensive structures which allow for conversion between heating and cooling functions.
One class of solar energy regulators or collectors of interest utilizes a plurality of louvers for various purposes. For example, U.S. Pat. No. 2,596,479 shows a louver type arrangement for use near a window. U.S. Pat. No. 2,969,918 discloses a plurality of louvers which can be positioned at different angles to vary the radiation transmitted thereby. U.S. Pat. No. 2,544,474 describes a system wherein the louvers function as pipes for the conduction of liquid. These, and most other prior techniques using louvers or "blinds," have not achieved commercial success for one or more reasons, including those discussed above; e.g., inefficiency or undue size, high cost, unsightliness, or lack of adaptability.
It is an object of the present invention to provide a solar energy system which overcomes the disadvantages of prior art systems as set forth.